About xbreaky
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xbreaky is a breakout game for X written by Dave Brul which can be downloaded
from http://xbreaky.sourceforge.net. xbreaky is added to the OpenBSD ports tree,
NetBSD tree and possibly others.

Problem
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By default xbreaky is installed as suid and can be abused to overwrite any file
on the filesystem, by any user.

Vulnerable versions
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All versions prior to 0.0.5

Exploit
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xbreaky uses $HOME/.breakyhighscores to write the highscores to, when
$HOME/.breakyhighscores is symlinked to another file (*any* file) it simply
overwrites it as root user.